1. Field of the Invention
The invention relates to an electrical connector assemblies for cables in motor vehicle electrical harnesses and more particularly to a backshell for fitting to end electrical connector for a cable which forces a preferred orientation of the electrical connector assembly relative to a device before connection can be made.
2. Description of the Prior Art
Harness and electrical cable connector assemblies are well known in the art. A motor vehicle electrical harness provides routing for electrical cables which transmit electrical power and control signals to diverse electrical and electronic devices positioned on a motor vehicle. Individual branches of the harness bundle cables and wires which service components in adjacent sections of a vehicle. A harness includes several large diameter cables enclosing smaller cables and wires inside a sheath. The sheath is typically constructed by winding a tape in a spiral fashion. Wires and cables in a harness are cut to predetermined lengths during manufacture of the harness and the ends of the wires and cables project from under the sheath at appropriate locations for connection to devices. During vehicle assembly workers can lay the harness along a predetermined path on the vehicle and the ends of the appropriate wires and cables to connect to vehicle accessories will automatically be positioned for attachment to devices. This saves considerable time during assembly and reduces the risk of connecting wires and cables to the wrong devices.
While the risk of incorrect connection of cables to devices is reduced by precutting the length of wires and cables, it is not eliminated in all cases. Wires and cables for automotive, and other applications, are typically terminated in a standardized connector, suitable for plug attachment to motors, sensors, switches and other devices. The Packard Electric Systems Division of Delphi Automotive Systems in Warren, Ohio, supplies the Metri-Pack connection systems, a family including at least five series of standardized terminators, designed to assure good seating and force correct orientation of the connector to device terminal.
Unfortunately, more than one device taking identical connectors may be in close proximity to one another on a vehicle, raising the possibility that two cables having identical connectors may emerge from a harness cord in close proximity to one another. Such an error would be easy to detect were, for example, control cables for a brake actuator and a vehicle horn crossed. Upon first depression of the brake pedal the horn would then sound. More serious, and more likely to occur, is the possibility that control cables leading to devices having similar functions might be crossed.
For example, in an anti-lock braking system (ABS) each brake is independently actuated in response to detection of skidding by the wheel associated with that brake. Brake actuation is controlled by a brake modulator valve. Due to space constraints and the lack of suitable mounting locations for the modulator valve, the valves for wheels on each end of a given axle, particularly the front steering axle, are often located in close physical proximity to one another. The electrical connecting cables for the modulators will then emerge from the harness in close physical proximity to one another, allowing the assembly worker or repair technician to cross the leads, which appear identical to one another. If the leads are crossed, indication of a skidding right wheel produces braking modulation for the left wheel and indication of a skidding left wheel produces braking modulation for the right wheel. The results can be difficult to detect in the field and, in an emergency, adverse to control of the vehicle.
The invention provides an electrical connector including an electrical cable connected to a terminal connector. The terminal connector is fabricated from a thermoplastic body and has an orientation guide on an exterior surface, A backshell is provided for fitting around the terminal connector and a portion of the cable adjacent to the terminal connector, The backshell comprises a first halfshell and a second halfshell connected on a hinge. The first and second halfshells form, when closed on one another, an interior channel accessible from the outside at two ends for receiving the electrical cable and the terminal connector, respectively. The first and second halfshells form, at the end for receiving the electrical cable, an opening shaped to fit around the cable circumference and further form, at the end for receiving the terminal connector, an opening shaped to fit around the terminal connector. The portion of the opening formed by the first halfshell fits around the orientation guide to force the backshell to assume a particular orientation on the terminal connector and electrical cable. The interior channel defines a turn, which combined with the forced orientation of the backshell, gives the electrical connector handedness. Depending on the direction of the turn, the electrical connector exhibits right or left handedness. Handedness prevents the wire or cable from being twisted to correctly orient the terminal connector to the device and still reach an Incorrect device accepting the terminal connector type.
Additional effects, features and advantages will be apparent in the written description that follows.